Reland "Apply global audio options at the engine level"

This is a reland of commit 1488f778a7b25c67c1c30dd9e11f9588d4b2ff38

Reland changes:
Move ownership of global audio options to ConnectionContext instead of
WebRtcVoiceEngine. That avoids an issue with a downstream implementation
where a premature Init/Terminate cycle occurred during CreateAudioSource

Original change's description:
> Apply global audio options at the engine level
>
> Introduce ApplyGlobalOptions to the MediaEngine interface to configure
> global audio processing options (such as AEC, AGC, and noise
> suppression) directly at the engine level. This replaces the previous
> behavior where media channels implicitly re-applied options to the
> engine during initialization and parameter updates.
>
> Applying global settings during CreateAudioSource ensures engine-level
> configurations persist reliably across stream lifecycles. This change
> also separates global audio processing options from stream-level
> parameters like jitter buffer and audio network adaptor settings.
>
>                  [Before Decoupling]
> +----------------------------------------------------+
> |      AudioOptions (AEC/AGC/NS + Jitter/ANA)        |
> +----------------------------------------------------+
>   /                                                \
>  / (engine()->ApplyOptions)                         \
> v                                                    v
> WebRtcVoiceEngine (Global APM)             VoiceSend/RecvChannel
>
>
>               [After Decoupling (This CL)]
> +-----------------------+                  +-----------------------+
> |  Global Options (APM) |                  |  Channel Options (ST) |
> |  - echo_cancellation  |                  |  - jitter_buffer      |
> |  - auto_gain_control  |                  |  - audio_network_     |
> |  - noise_suppression  |                  |    adaptor            |
> +-----------------------+                  +-----------------------+
>            |                                           |
>            v (ApplyGlobalOptions)                      v
>    WebRtcVoiceEngine (APM)                     VoiceSend/RecvChannel
>    - Stores in global_options_                 - No ApplyOptions calls
>    - Persisted across cycles                   - No leakage / racing
>
> Bug: webrtc:42224170
> Change-Id: I3c23293ae338495ee32330ce5287411947f6d472
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/476340
> Reviewed-by: Per Åhgren <peah@webrtc.org>
> Commit-Queue: Tomas Gunnarsson <tommi@webrtc.org>
> Cr-Commit-Position: refs/heads/main@{#47844}

Bug: webrtc:42224170
Change-Id: I2e3b0374885c5f8daf25cc2fd62b56653574c13e
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/476782
Reviewed-by: Per Åhgren <peah@webrtc.org>
Commit-Queue: Tomas Gunnarsson <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#47867}